Half a century ago, the unthinkable became all too thinkable as the Soviet Union and the United States engaged in a game of chicken, played with nuclear bombs.

On Oct. 22, 1962, President John F. Kennedy went on television to announce that the Soviet Union was building missile bases in Cuba. Declaring that intolerable, a stern-faced Kennedy called upon Soviet premier Nikita Khrushchev to remove those "weapons of sudden mass destruction."

"We will not prematurely or unnecessarily risk the costs of worldwide nuclear war in which even the fruits of victory would be ashes in our mouth — but neither will we shrink from that risk at any time it must be faced," Kennedy said.

The world had dreaded hearing such words ever since the Soviet Union developed its atomic bomb in 1949 — an achievement U.S. officials had thought was years away.

The Atomic Age was born in Chicago, accompanied by wonder and pride in the power of science, but it morphed into an age of anxiety. The Cold War had its own scary vernacular — terms like duck and cover, ground zero, blast range, nuclear winter. It was an era of bomb shelters, Nike missiles and eventually ICBMs — and a persistent feeling that doomsday was at hand.

Luigi Mendicino / Chicago Tribune

Soldiers fuel a guided missile during a 1955 demonstration for members of the Institute of Radio Engineers in Jackson Park.

Soldiers fuel a guided missile during a 1955 demonstration for members of the Institute of Radio Engineers in Jackson Park.

(Luigi Mendicino / Chicago Tribune)

On Sept. 23, 1949, one month after the Soviets tested their A-bomb, a group of scientists at the University of Chicago who had worked on America's bomb held a news conference to share their gloomy assessment of how the Russian weapon altered the Cold War. Among them was Harold Urey, a Nobel prize winner who played a key role in the Manhattan Project.

"Urey said he saw no defense assurance within 50 years, other than political organization, that would 'keep the people of Chicago from getting killed' in case of atomic bomb attack," the Tribune reported. Other Chicagoans — either unwilling to wait that long or not trusting politicians — dug in, some literally so.

William Vendetta / Chicago Tribune

Radar for the Nike missile installation at Montrose Harbor sweeps the skies seeking out aircraft in 1960. The radar apparatus is manned 24/7 by full crews.

Radar for the Nike missile installation at Montrose Harbor sweeps the skies seeking out aircraft in 1960. The radar apparatus is manned 24/7 by full crews.

(William Vendetta / Chicago Tribune)

In 1961, Chicago Fire Commissioner Robert J. Quinn thought a limestone quarry in the Bridgeport neighborhood could become a bomb shelter. Its owner, Material Service, said that "excavations are progressing there at a rate sufficient to provide the equivalent of a three room apartment each day," the Tribune noted.

Some proposed that a planned Grant Park underground garage double as a shelter. And a Lombard village trustee wanted similar specifications for any new sewers in that suburb.

Also in 1961, at the height of the shelter-building craze, the Chicago City Council entertained an ordinance requiring that anyone building a shelter pay $15 for a permit. That same year, the Tribune did a six-part series on shelters.

Decades afterward, Al Rolla, then 41, recalled for a Tribune reporter "the excitement he felt when he saw a neighbor's yard in Morton Grove being dug up by workers. The 8-year old boy thought the block was getting a swimming pool. Instead, he was told, the neighborhood was getting a fallout shelter."

The Tribune didn't wait on the Soviets before starting its own quest for safety from a nuclear blast. Two years before the Russian bomb, it announced that Walter Zinn, director of the Argonne National Laboratory, would advise the newspaper on how to transform Tribune Tower's basement floors into "a self-contained city, sealed from outside air, and with food, water, methods for communicating with the outside world, tools for digging out from beneath tons of debris, medical supplies, and all the latest equipment to combat atomic burns and debilitation."

Three weeks after the Soviet atomic test, the Tribune revealed updated plans for protecting employees. A cutaway drawing of the tower showed shelters not just underground, but also on upper floors, where rolls of newsprint would reinforce the building's structural framework.

"To inform the Tribune population and others in the neighborhood that an atomic bomb attack is imminent, a steamboat whistle soon is to be installed on the seventh floor of the light court behind the Tribune Tower," the paper noted.

Anthony Turkevich, a U. of C. physicist, endorsed the Tribune's plans: "If I had to make the choice of being out in the streets or in your shelter at the time an atomic bomb exploded, I would prefer your shelter."

The Tribune also gave voice to the opposite view. A story about what to do in case of an atomic attack carried a headline that got right to the point: "Don't Stick Around." The paper printed a map showing concentric rings of destruction radiating out from a bomb that destroyed the city's center. "Only the stubs of buildings would be left as far north as Division street, as far south as 16th street, as far east as the lake, and as far west as Racine avenue," one article forecast.

Reinforcing the siege mentality of those years, about 20 anti-aircraft missile bases ringed the Chicago metro area, including installations in Jackson Park, Montrose Harbor, Arlington Heights, Homewood, Orland Park and Gary. Whether or not they would have provided protection in case of an enemy attack, they gave visual witness to the fact that a political miscalculation by either superpower could ignite an atomic Armageddon.

The first generation of Nike missiles was armed with conventional explosives. When later ones carried nuclear warheads, government authorities hastened to reassure the public that stationing atomic bombs close to cities posed no danger to their inhabitants.

A 1957 Tribune report said Pentagon officials described the Nike-Hercules as a "rocket with an atomic warhead that not only destroys enemy bombers but 'cooks' away their H-bombs." Not everyone was convinced that they were safe or effective, including Rep. Daniel Rostenkowski, who wanted them removed.

"If an enemy bomber can penetrate 800 miles within our (coastal) defense system then we are in more serious trouble than the Pentagon has indicated," he told the Tribune in 1971. "If they cannot, then the Nike bases are unnecessary."

As it turned out, the Nikes were never launched. The Cuban missile crisis ended — after days of heart-in-your-throat tension — when Khrushchev removed the Soviet weapons from Cuba.

In the 1970s, the remaining Nike bases were dismantled, and some became teenage hangouts. Uncounted bomb shelters became historical oddities or expensive root cellars.

Yet for those who lived through the era of fear of atomic annihilation, the memories went with them.

Vince Persico, who grew up to be a state representative from Glen Ellyn, retained clear images of his family glued to the television during the Cuban missile crisis.

"I can remember my father saying, 'This could be the end of civilization as we know it,' Persico told the Tribune, 29 years later. "When your father's that nervous, and you can see the tension in his face, you know it's something severe."

Editor's note: Thanks to Jim Paskiewicz of Algonquin for suggesting this Flashback.